code: def test_schultz_and_gutman_index_of_disconnected_graph():
      n = 4
      G = nx.Graph()
      G.add_nodes_from(list(range(1, n + 1)))
      expected = float("inf")
  
      G.add_edge(1, 2)
      G.add_edge(3, 4)
  
      actual_1 = nx.schultz_index(G)
      actual_2 = nx.gutman_index(G)
  
      assert expected == actual_1
      assert expected == actual_2
  
file_path: networkx/networkx/algorithms/tests/test_wiener.py
imports: import networkx
label_desc: Use image node_id 5 for calling a global function with example usage: test_schultz_and_gutman_index_of_disconnected_graph() without return types